Face recognition system for face recognition in unlabeled videos with domain adversarial learning and knowledge distillation

ABSTRACT

A face recognition system is provided that includes a device configured to capture a video sequence formed from a set of unlabeled testing video frames. The system includes a processor configured to pre-train a face recognition engine formed from reference CNNs on a still image domain that includes labeled training still image frames of faces. The processor adapts the face recognition engine to a video domain to form an adapted engine, by applying non-reference CNNs to domains including the still image and video domains and a degraded image domain. The degraded image domain includes labeled synthetically degraded versions of the frames included in the still image domain. The video domain includes random unlabeled training video frames. The processor recognizes, using the adapted engine, identities of persons corresponding to at least one face in the video sequence to obtain a set of identities. A display device displays the set of identities.

RELATED APPLICATION INFORMATION

This application claims priority to provisional application Ser. No.62/472,896, filed on Mar. 17, 2017, incorporated herein by reference.This application is related to an application entitled “Recognition InUnlabeled Videos With Domain Adversarial Learning And KnowledgeDistillation”, having attorney docket number 16098A, and which isincorporated by reference herein in its entirety. This application isrelated to an application entitled “Surveillance System For RecognitionIn Unlabeled Videos With Domain Adversarial Learning And KnowledgeDistillation”, having attorney docket number 16098C, and which isincorporated by reference herein in its entirety. This application isrelated to an application entitled “Action Recognition System For ActionRecognition In Unlabeled Videos With Domain Adversarial Learning AndKnowledge Distillation”, having attorney docket number 16098D, and whichis incorporated by reference herein in its entirety.

BACKGROUND Technical Field

The present invention relates to video recognition, and moreparticularly to a face recognition system for face recognition inunlabeled videos with domain adversarial learning and knowledgedistillation.

Description of the Related Art

In machine learning, there exists the fundamental problem of domainadaptation when the source domain has abundant labeled training data andthe target domain has no or little labeled training data but a massiveamount of unlabeled data.

Accordingly, there is a need for a solution to the aforementionedproblem relating to unlabeled data.

SUMMARY

According to an aspect of the present invention, a face recognitionsystem is provided. The face recognition system includes a video capturedevice configured to capture a video sequence formed from a set ofunlabeled testing video frames. The video sequence including one or morefaces. The face recognition system further includes a processor. Theprocessor is configured to pre-train a face recognition engine formedfrom a reference set of convolutional neural networks (CNNs) on a stillimage domain that includes a set of labeled training still image framesof faces. The processor is further configured to adapt the facerecognition engine to a video domain to form an adapted face recognitionengine, by applying a non-reference set of CNNs to a set of domains thatinclude the still image domain, a synthetically degraded image domain,and the video domain. The synthetically degraded image domain includeslabeled synthetically degraded versions of the labeled training stillimage frames included in the still image domain. The video domainincludes random unlabeled training video frames. The processor is alsoconfigured to recognize, using the adapted face recognition engine,identities of persons corresponding to at least one of the faces in thevideo sequence to obtain a set of identities for recognized ones of thepersons. The face recognition system also includes a display deviceconfigured to display the set of recognized identities to a user.

According to another aspect of the present invention, acomputer-implemented method is provided for face recognition. The methodincludes capturing, by a video capture device, a video sequence formedfrom a set of unlabeled testing video frames. The video sequenceincludes one or more faces. The method further includes pre-training, bya processor, a face recognition engine formed from a reference set ofconvolutional neural networks (CNNs) on a still image domain thatincludes a set of labeled training still image frames of faces. Themethod also includes adapting, by the processor, the face recognitionengine to a video domain to form an adapted face recognition engine, byapplying a non-reference set of CNNs to a set of domains that includethe still image domain, a synthetically degraded image domain, and thevideo domain. The synthetically degraded image domain includes labeledsynthetically degraded versions of the labeled training still imageframes included in the still image domain. The video domain includesrandom unlabeled training video frames. The method additionally includesrecognizing, by the processor using the adapted face recognition engine,identities of persons corresponding to at least one of the faces in thevideo sequence to obtain a set of identities for recognized ones of thepersons. The method further includes displaying, by a display device,the set of recognized identities to a user.

According to yet another aspect of the present invention, a computerprogram product is provided for face recognition. The computer programproduct includes a non-transitory computer readable storage mediumhaving program instructions embodied therewith. The program instructionsare executable by a computer to cause the computer to perform a method.The method includes capturing, by a video capture device, a videosequence formed from a set of unlabeled testing video frames. The videosequence includes one or more faces. The method further includespre-training, by a processor, a face recognition engine formed from areference set of convolutional neural networks (CNNs) on a still imagedomain that includes a set of labeled training still image frames offaces. The method also includes adapting, by the processor, the facerecognition engine to a video domain to form an adapted face recognitionengine, by applying a non-reference set of CNNs to a set of domains thatinclude the still image domain, a synthetically degraded image domain,and the video domain. The synthetically degraded image domain includeslabeled synthetically degraded versions of the labeled training stillimage frames included in the still image domain. The video domainincludes random unlabeled training video frames. The method additionallyincludes recognizing, by the processor using the adapted facerecognition engine, identities of persons corresponding to at least oneof the faces in the video sequence to obtain a set of identities forrecognized ones of the persons. The method further includes displaying,by a display device, the set of recognized identities to a user.

These and other features and advantages will become apparent from thefollowing detailed description of illustrative embodiments thereof,which is to be read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The disclosure will provide details in the following description ofpreferred embodiments with reference to the following figures wherein:

FIG. 1 shows an exemplary system for face recognition in unlabeledvideos with domain adversarial learning and knowledge distillation, inaccordance with an embodiment of the present invention;

FIG. 2 shows an exemplary system for object recognition in unlabeledvideos with domain adversarial learning and knowledge distillation, inaccordance with an embodiment of the present invention;

FIG. 3 shows an exemplary system for surveillance based on recognitionin unlabeled videos with domain adversarial learning and knowledgedistillation, in accordance with an embodiment of the presentprinciples;

FIG. 4 shows an exemplary system for action recognition in unlabeledvideos with domain adversarial learning and knowledge distillation, inaccordance with an embodiment of the present invention;

FIG. 5 shows an exemplary processing system to which the presentprinciples may be applied, according to an embodiment of the presentprinciples;

FIG. 6 shows an exemplary training protocol for recognition in unlabeledvideos, in accordance with an embodiment of the present invention;

FIG. 7 shows an exemplary testing protocol for face recognition inunlabeled videos, in accordance with an embodiment of the presentinvention;

FIG. 8 shows an exemplary training protocol with loss formulation forrecognition in unlabeled videos, in accordance with an embodiment of thepresent invention;

FIGS. 9-14 show an exemplary method for recognition in unlabeled videoswith domain adversarial learning and knowledge distillation, inaccordance with an embodiment of the present principles;

FIG. 15 shows an exemplary architecture, in accordance with anembodiment of the present invention; and

FIG. 16 further shows the architecture of FIG. 15, in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention is directed to a face recognition system for facerecognition in unlabeled videos with domain adversarial learning andknowledge distillation.

In an embodiment, the present invention solves the fundamental machinelearning problem of domain adaptation where the source domain hasabundant labeled training data and the target domain has no or only afew numbers of labeled training data but a massive amount of unlabeleddata.

In an embodiment, the present invention utilizes unlabeled video data totrain a recognition engine together with labeled image data.

In an embodiment, the present invention is applied to video facerecognition. Of course, the present invention is not limited to solelyvideo face recognition and can be applied to other types of recognition,as readily appreciated by one of ordinary skill in the art given theteachings of the present invention provided herein, while maintainingthe spirit of the present invention.

In an embodiment, the present invention can provide and/or otherwiseinvolve one or more of the following:

(a) a new training framework for deep metric learning with labeled datafrom a source domain and unlabeled data from a target domain;(b) a synthetically blurred image domain to bridge the gap between thetwo aforementioned domains (that is, the image domain and the videodomain);(c) a series of training objectives, such as, for example, featurematching loss, and feature restoration loss, classification loss, aswell as adversarial loss, to train our network; and(d) a proposed training framework that allows a recognition engine tohave better generalization ability to the target domain.

It is to be appreciated that recognition in unlabeled videos inaccordance with the present invention can be applied to applicationsincluding, but not limited to, any of the following: face recognition;surveillance; action recognition; and so forth. Of course, the presentinvention can also be applied to a myriad of other applications, asreadily appreciated by one of ordinary skill in the art given theteachings of the present invention provided herein, while maintainingthe spirit of the present invention.

FIG. 1 shows an exemplary system 100 for face recognition in unlabeledvideos with domain adversarial learning and knowledge distillation, inaccordance with an embodiment of the present invention.

The system 100 includes a camera system 110. While a single camerasystem 110 is shown in FIG. 1 for the sakes of illustration and brevity,it is to be appreciated that multiple camera systems can be also used,while maintaining the spirit of the present invention.

In the embodiment of FIG. 1, the camera system 110 is mounted on amounting entity 160. For the sake of illustration, the mounting entity160 is a pole. While a pole 160 is shown (as a mounting entity) for thesake of illustration, any other mounting entity can be used, as readilyappreciated by one of ordinary skill in the art given the teachings ofthe present invention provided herein, while maintaining the spirit ofthe present invention. For example, the camera system 110 can be mountedin or on any of the following: a building; a drone; a vehicle; and soforth. The preceding examples are merely illustrative.

The camera system 110 can be a wireless camera system having its ownantenna(s) or can use one or more antennas included on the pole 160 (orother mounting entity (e.g., building, drone, vehicle, etc.) to whichthe camera system 110 is mounted or proximate).

The system 100 further includes a server 120 configured to perform facerecognition in unlabeled videos. The face recognition can involverecognizing a person 188 using face recognition. In the embodiment ofFIG. 1, the person 188 is located in a motor vehicle 172. The facerecognition can further involve performing one or more actions (e.g., inresponse to particular face recognition results). The server 120 canlocated remote from, or proximate to, the camera system 110. The server120 can include, e.g., a processor 121, a memory 122, and a wirelesstransceiver 123. The processor 121 and the memory 122 of the removeserver 120 can be configured to perform face recognition based on imagesreceived from the camera system 110 by the (the wireless transceiver 123of) the remote server 120. In this way, a list 199 of recognized personscan be provided for any of a myriad of possible application usesrelating to face recognition. Such application uses can involve one ormore actions performed responsive to the list, as readily appreciated byone of ordinary skill in the art.

Accordingly, some exemplary suitable environments to which the presentinvention can be applied can include any environments where facerecognition can be used. For example, exemplary suitable environmentsinclude, but are not limited to, an environment to be surveilled, asports or other event, a battle field, a riot scenario, a picketingscenario, video analysis, a mass transit hub, and so forth.

FIG. 2 shows an exemplary system 200 for object recognition in unlabeledvideos with domain adversarial learning and knowledge distillation, inaccordance with an embodiment of the present invention.

The system 200 includes a camera system 210. While a single camerasystem 210 is shown in FIG. 2 for the sakes of illustration and brevity,it is to be appreciated that multiple camera systems can be also used,while maintaining the spirit of the present invention.

In the embodiment of FIG. 2, the camera system 210 is mounted on amounting entity 260. For the sake of illustration, the mounting entity260 is a pole. While a pole 260 is shown (as a mounting entity) for thesake of illustration, any other mounting entity can be used, as readilyappreciated by one of ordinary skill in the art given the teachings ofthe present invention provided herein, while maintaining the spirit ofthe present invention. For example, the camera system 210 can be mountedin or on any of the following: a building; a drone; a vehicle; and soforth. The preceding examples are merely illustrative.

The camera system 210 can be a wireless camera system having its ownantenna(s) or can use one or more antennas included on the pole 260 (orother mounting entity (e.g., building, drone, vehicle, etc.) to whichthe camera system 210 is mounted or proximate).

The system 200 further includes a server 220 configured to performobject recognition in unlabeled videos. The object recognition caninvolve detecting the presence of multiple objects 288, recognizing themultiple objects 288, identifying particular actions performed by themultiple objects 288, and/or performing one or more actions (e.g., inresponse to particular object recognition results). The server 220 canlocated remote from, or proximate to, the camera system 210. The server220 can include, e.g., a processor 221, a memory 222, and a wirelesstransceiver 223. The processor 221 and the memory 222 of the removeserver 220 can be configured to perform object recognition based onimages received from the camera system 210 by the (the wirelesstransceiver 223 of) the remote server 220. In this way, a list 299 ofrecognized objects can be provided for any of a myriad of possibleapplication uses relating to object recognition. Such application usescan involve one or more actions performed responsive to the list, asreadily appreciated by one of ordinary skill in the art.

Accordingly, some exemplary suitable environments to which the presentinvention can be applied can include any environments where objectrecognition can be used. For example, exemplary suitable environmentsinclude, but are not limited to, an environment to be surveilled, asports or other event, a battle field, a riot scenario, a picketingscenario, video analysis, a mass transit hub, and so forth.

FIG. 3 shows an exemplary system 300 for surveillance based onrecognition in unlabeled videos with domain adversarial learning andknowledge distillation, in accordance with an embodiment of the presentprinciples.

The system 300 includes a camera system 310. While a single camerasystem 310 is shown in FIG. 3 for the sakes of illustration and brevity,it is to be appreciated that multiple camera systems can be also used,while maintaining the spirit of the present invention.

In the embodiment of FIG. 3, the camera system 310 is mounted on amounting entity 360. For the sake of illustration, the mounting entity360 is a pole. While a pole 360 is shown (as a mounting entity) for thesake of illustration, any other mounting entity can be used, as readilyappreciated by one of ordinary skill in the art given the teachings ofthe present invention provided herein, while maintaining the spirit ofthe present invention. For example, the camera system 310 can be mountedin or on any of the following: a building; and so forth. The precedingexamples are merely illustrative.

The camera system 310 can be a wireless camera system having its ownantenna(s) or can use one or more antennas included on the pole 360 (orother mounting entity (e.g., building, drone, etc.) to which the camerasystem 310 is mounted or proximate).

The system 300 further includes a server 320 configured to performsurveillance based on object recognition in unlabeled videos. Suchsurveillance can be with respect to a secured object such as, forexample, a secured facility 377. Such surveillance can be with respectto an object at the secured facility 377, such as a car 388. In theexample of FIG. 3, the secured facility is an airport. Of course, othersecured facilities can also be surveilled in accordance with the presentinvention. The surveillance can involve detecting the presence ofobjects, recognizing the objects, identifying particular actionsperformed by the objects, and/or performing one or more actions (e.g.,in response to object recognition/surveillance results). The server 320can be located remote from, or proximate to, the camera system 310. Theserver 320 can include a processor 321, a memory 322, and a wirelesstransceiver 323. The processor 321 and the memory 322 of the remoteserver 320 can be configured to perform surveillance based on imagesreceived from the camera system 310 by the (the wireless transceiver 323of) the remote server 320. In this way, a list 399 of recognized objectscan be provided for any of a myriad of possible surveillance applicationuses relating to object recognition. Such application uses can involveone or more actions performed responsive to the list, as readilyappreciated by one of ordinary skill in the art. For example, an alert(local and/or remote) can be provided, one or more doors and/or windowscan be closed and locked to secure the person within a specific area orto keep the person from (out of) that specific area, a personcontainment procedure can be automatically performed, and so forth.

Accordingly, some exemplary suitable environments to which the presentinvention can be applied can include any environments where surveillancecan prove useful such as mass transit hubs, border crossings, subways,transportation hubs, airports, ship ports, and so forth. It is to beappreciated that the preceding environments are merely illustrative and,thus, other environments can also be used, while maintaining the spiritof the present invention.

FIG. 4 shows an exemplary system 400 for action recognition in unlabeledvideos with domain adversarial learning and knowledge distillation, inaccordance with an embodiment of the present invention.

The system 400 includes a camera system 410. While a single camerasystem 410 is shown in FIG. 4 for the sakes of illustration and brevity,it is to be appreciated that multiple camera systems can be also used,while maintaining the spirit of the present invention.

In the embodiment of FIG. 4, the camera system 410 is mounted on amounting entity 460. For the sake of illustration, the mounting entity460 is a pole. While a pole 460 is shown (as a mounting entity) for thesake of illustration, any other mounting entity can be used, as readilyappreciated by one of ordinary skill in the art given the teachings ofthe present invention provided herein, while maintaining the spirit ofthe present invention. For example, the camera system 410 can be mountedin or on any of the following: a building; and so forth. The precedingexamples are merely illustrative.

The camera system 410 can be a wireless camera system having its ownantenna(s) or can use one or more antennas included on the pole 460 (orother mounting entity (e.g., building, drone, etc.) to which the camerasystem 410 is mounted or proximate).

The system 400 further includes a server 420 configured to performaction recognition in unlabeled videos. Such action recognition can bewith respect to a secured object such as, for example, a facility 477.The facility can be a secured facility or a non-secured facility. In theexample of FIG. 4, the facility is a secured facility implemented as anairport. Of course, other facilities (e.g., mass transit hub, sportscomplex, etc.) can also be monitored with respect to action recognitionin unlabeled videos in accordance with the present invention. The actionrecognition can involve detecting the presence of objects 488 (e.g.,persons), recognizing particular actions performed by the objects 488and/or particular actions performed by one or more persons using theobjects 488, and/or performing one or more actions (e.g., in response toaction recognition results). The server 420 can be located remote from,or proximate to, the camera system 410. The server 420 can include aprocessor 421, a memory 422, and a wireless transceiver 423. Theprocessor 421 and the memory 422 of the remote server 420 can beconfigured to perform surveillance based on images received from thecamera system 410 by the (the wireless transceiver 423 of) the remoteserver 420. In this way, a list 499 of recognized actions can beprovided for any of a myriad of possible application uses relating toaction recognition. Such application uses can involve one or moreactions performed responsive to the list, as readily appreciated by oneof ordinary skill in the art. For example, an alert (local and/orremote) can be provided, one or more doors and/or windows can be closedand locked to secure the person within a specific area or to keep theperson from (out of) that specific area, a person containment procedurecan be automatically performed, and so forth.

Accordingly, some exemplary suitable environments to which the presentinvention can be applied can include any environments where actionrecognition can prove useful such as mass transit hubs, bordercrossings, subways, transportation hubs, airports, ship ports, sportsfacilities, and so forth. It is to be appreciated that the precedingenvironments are merely illustrative and, thus, other environments canalso be used, while maintaining the spirit of the present invention.

Any action type of interest can be recognized, depending upon theimplementation. For example, the action may include, but is not limitedto, one or more of the following: an intruder running up to a premisesor an object; a projectile approaching the premises or the object; asporting action; a prohibited action (e.g., holding a weapon in a placewhere weapons are prohibited except for, e.g., law enforcement, etc.); apotentially dangerous action; and so forth. It is to be appreciated thatthe preceding actions are merely illustrative.

FIG. 5 shows an exemplary processing system 500 to which the presentprinciples may be applied, according to an embodiment of the presentprinciples. In an embodiment, the server 120 of FIG. 1 and/or the server220 of FIG. 2 and/or the server 320 of FIG. 3 and/or the server 420 ofFIG. 4 can be implemented, at least in part, by processing system 500.

The processing system 500 includes at least one processor (CPU) 504operatively coupled to other components via a system bus 502. A cache506, a Read Only Memory (ROM) 508, a Random Access Memory (RAM) 510, aninput/output (I/O) adapter 520, a sound adapter 530, a network adapter540, a user interface adapter 550, and a display adapter 560, areoperatively coupled to the system bus 502.

A first storage device 522 and a second storage device 524 areoperatively coupled to system bus 502 by the I/O adapter 520. Thestorage devices 522 and 524 can be any of a disk storage device (e.g., amagnetic or optical disk storage device), a solid state magnetic device,and so forth. The storage devices 522 and 524 can be the same type ofstorage device or different types of storage devices.

A speaker 532 is operatively coupled to system bus 502 by the soundadapter 530. A transceiver 542 is operatively coupled to system bus 502by network adapter 540. A display device 562 is operatively coupled tosystem bus 502 by display adapter 560.

A first user input device 552, a second user input device 554, and athird user input device 556 are operatively coupled to system bus 502 byuser interface adapter 550. The user input devices 552, 554, and 556 canbe any of a keyboard, a mouse, a keypad, an image capture device, amotion sensing device, a microphone, a device incorporating thefunctionality of at least two of the preceding devices, and so forth. Ofcourse, other types of input devices can also be used, while maintainingthe spirit of the present principles. The user input devices 552, 554,and 556 can be the same type of user input device or different types ofuser input devices. The user input devices 552, 554, and 556 are used toinput and output information to and from system 500.

Of course, the processing system 500 may also include other elements(not shown), as readily contemplated by one of skill in the art, as wellas omit certain elements. For example, various other input devicesand/or output devices can be included in processing system 500,depending upon the particular implementation of the same, as readilyunderstood by one of ordinary skill in the art. For example, varioustypes of wireless and/or wired input and/or output devices can be used.Moreover, additional processors, controllers, memories, and so forth, invarious configurations can also be utilized as readily appreciated byone of ordinary skill in the art. These and other variations of theprocessing system 500 are readily contemplated by one of ordinary skillin the art given the teachings of the present principles providedherein.

Moreover, it is to be appreciated that systems 100, 200, 300, and 400described above with respect to FIGS. 1, 2, 4, and 4, respectively, aresystems for implementing respective embodiments of the presentprinciples. Part or all of processing system 500 may be implemented inone or more of the elements of any of systems 100, 200, 300, and 400.

Further, it is to be appreciated that system 500 may perform at leastpart of the method described herein including, for example, at leastpart of method 900 of FIGS. 9-14. Similarly, part or all of any ofsystems 100, 200, 300, and/or 400 may be used to perform at least partof method 900 of FIGS. 9-14.

FIG. 6 shows an exemplary training protocol 600 for recognition inunlabeled videos, in accordance with an embodiment of the presentinvention.

The training protocol 600 includes an image domain 601, an image domain602, a synthetic image domain 603, and a video frame domain 604.

The image domain 601 includes labeled still images of preferably highquality. The image domain 602 includes original labeled still images andthe synthetic image domain 603 includes transformed versions of theoriginal still images in the image domain 602. In an embodiment, theimage domain 601 can include domain-specific faces (faces expected in agiven domain), while the image domain 602 can include domainnon-specific (e.g., random) faces. The video frame domain 604 includesunlabeled video frames.

The training protocol 600 further includes a reference deepConvolutional Neural Network (CNN) 611, a deep CNN 612, a deep CNN 613,and a deep CNN 614.

The image domain 601 is operatively coupled to the reference deep CNN611. The image domain 602 is operatively coupled to the deep CNN 612.The synthetic image domain 603 is operatively coupled to the deep CNN613. The video frame domain 604 is operatively coupled to the deep CNN614.

In an embodiment, the image domain 601 and the reference domain form areference net or “RFNet” as described in further detail herein. RFNetcan be considered to form a pre-trained face recognition engine on alabeled web face database. In an embodiment, the image domain 602, thesynthetic image domain 603, the video frame domain 604, the deep CNN612, the deep CNN 613, and the deep CNN 614 form a video face network or“VDNET”. VDNet is trained by distilling discriminative knowledge fromRFNet. In an embodiment, RFNet can be exactly the same as the facerecognition engine and the parameters can be fixed over the training.VDNet can be initialized the same as RFNet but the parameters areupdated for all layers except the last two convolutional layers.

The training protocol 600 also includes a feature reconstruction loss621, a feature restoration loss 622, and domain-adversarial loss 623.

The feature reconstruction loss 621 is used to maintain the goodperformance of the network on high-quality images.

The feature restoration loss 622 is used to restore the representationof low-quality images.

The domain-adversarial loss 623 involves a 3-way discriminator 623A. Thedomain-adversarial loss 623 is used to reduce the differences betweenthree domains, namely, the image domain 602, the synthetically blurredimage domain 603, and the video domain 604. Furthermore, thediscriminator's confidence score can be used for attention at test time.

FIG. 7 shows an exemplary testing protocol 700 for face recognition inunlabeled videos, in accordance with an embodiment of the presentinvention.

The testing protocol 700 includes, for each feature, a set of videoframes 701A through 701N, a set of deep CNNs 721A through 721N, a set ofmultipliers 731A through 731N, a set of discriminator outputs 741Athrough 741N, and a respective summer 750.

Each of the video frames 701A through 701N in the set is operativelycoupled to an input of a respective one of the deep CNNs 721A through721N. The networks 721A through 721N are configured the same withrespect to each other. That is, the same network is repeatedly used(with each repeat having its own letter (A through N) after 721) foreach frame to be processed in accordance with the present invention.

An output of the each of the deep CNNs 721A through 721N is operativelycoupled to an input of a respective one of the multipliers 731A through731N and to a respective one of the discriminator outputs 741A through741N that is also provided as an input to a respective one of themultipliers 731A through 731N.

Outputs of the multipliers 731A through 731N are operatively coupled tothe respective summer 750 for that feature in order to output arespective feature. The features are used to form a classifier 760.

FIG. 8 shows an exemplary training protocol 800 with loss formulationfor recognition in unlabeled videos, in accordance with an embodiment ofthe present invention.

The training protocol 800, similar to FIG. 6, includes an image domain601, an image domain 602, a synthetic image domain 603, and a videoframe domain 604.

The training protocol 800 further includes a reference deepConvolutional Neural Network (CNN) 811, a reference deep CNN 812, a deepCNN 813, a deep CNN 814, a deep CNN 815, a deep CNN 816, and a deep CNN817. Note that the aforementioned image domains 801-804 are shared bythe CNNs 811-817 as described below.

Of the CNNs 811-817, CNNs 811 and 813 are RFNET as described herein, andCNNs 812 and 814-817 are VDNET as described herein. For correlation toFIG. 6, CNNs 811 and 813 of FIG. 8 can correspond to CNN 611 of FIG. 6,CNNs 812 and 815 of FIG. 8 can correspond to CNN 612 of FIG. 6, CNNs 814and 816 of FIG. 8 can correspond to CNN 613 of FIG. 6, and CNN 817 ofFIG. 8 can correspond to CNN 614 of FIG. 6.

The image domain 601 is operatively coupled to the reference deep CNN611, the reference deep CNN 813, and the deep CNN 815. The image domain602 is operatively coupled to the deep CNN 812. The synthetic imagedomain 603 is operatively coupled to the deep CNN 613 and the deep CNN615. The video frame domain 604 is operatively coupled to the deep CNN617.

FIGS. 9-14 show an exemplary method 900 for recognition in unlabeledvideos with domain adversarial learning and knowledge distillation, inaccordance with an embodiment of the present principles.

Referring to FIG. 9, at block 910, capture, by a video capture device, avideo sequence formed from a set of unlabeled testing still imageframes. The video sequence includes a set of objects.

At block 920, pre-train, by a processor, a recognition engine on a stillimage domain that includes a set of labeled training still image frames.In an embodiment, pre-training of the recognition engine can beperformed by matching feature representations between a reference CNNand at least one non-reference CNN. In an embodiment, matching thefeature representations can include computing a feature matching lossfor an image frame processed by the reference CNN and the non-referenceCNN. The feature matching loss can be used for acquiring discriminationinformation relating to object recognition.

In an embodiment, block 920 can include one or more of blocks 920A-920C.

At block 920A, modify, by the processor using a discriminator configuredto perform adversarial learning, video frames to have similar featuredistributions to the still image frames. In an embodiment, theadversarial learning can be performed using an adversarial loss metric.In an embodiment, the discriminator can be configured to use a 2-waysoftmax classifier to discriminate between the still image domain and anintegrated domain formed from the video domain and the syntheticallydegraded image domain. In another embodiment, the discriminator can beconfigured to use a 3-way softmax classifier to discriminate between thestill image domain and the domains of video and synthetically degradedimages.

At block 920B, assign, by the discriminator, a respective confidencescore indicative of quality to each of video frames in the video domain,and the processor is configured to reject any of the video frames havingthe respective confidence score below a threshold value.

Referring to FIG. 10, at block 920C, apply one or more outputs of thediscriminator on a feature space relating to video images in the videodomain.

At block 930, adapt, by the processor, the recognition engine to a videodomain to form an adapted recognition engine, by applying a set ofconvolutional neural networks to a set of domains that include the stillimage domain, the video domain, and a synthetically degraded imagedomain. The synthetically degraded image domain includes syntheticallydegraded versions of image frames included in the still image domain.The synthetically degraded versions of image frames can include blurredimage frames, compressed image frames, and image frames that have beensubjected to one or more transformations.

At block 940, recognize, by the processor using the adapted recognitionengine, one or more of the objects in the video sequence to obtain a setof recognized objects.

At block 950, display, by a display device, the set of recognizedobjects to a user.

At step 960, perform one or more actions based on the set of recognizedobjects. For example, the one or more actions can be directed to one ormore of the following: object recognition; face recognition;surveillance; action recognition; and so forth.

In an embodiment, step 960 can include one or more of steps 960A through960D.

Referring to FIG. 11, at step 960A, corresponding to object detection,perform one or more actions that can include, but are not limited to,one or more of the following: generate an image showing the objects;provide a user-perceptible object detection result to a user; performone or more actions relating to a result of the object detection. In anembodiment, the user-perceptible object detection result can be in theform of a list of detected objects which is displayed on a displaydevice and/or provided through a speaker. The actions that can beperformed include, but are not limited to, can relate to any of thefollowing: object (person, pedestrian, animal, weapon, food, etc.)detection; object tracking (e.g., retail (tracking customer path inshopping stores, airport or train station shopping malls), smarttransportation (tracking and regulating passenger or vehicle flow inairports, bus and train stations), security (monitor individuals foraccess control), safety (evacuating people in emergency situations));and so forth. Other actions relating to a Face Recognition System, asurveillance system, and an action recognition system are also describedherein below.

Referring to FIG. 12, at step 960B, corresponding to face recognition,perform one or more actions that can include, but are not limited to,one or more of the following: permit access, by a recognized individual,to an object, a device, a system, a service, and/or so forth;deny/restrict access, by an unrecognized individual, to an object, adevice, a system, a service, and/or so forth. Such access can involveunlocking a lock, and so forth. Such access denial can involve locking alock, and so forth.

Referring to FIG. 13, at step 960C, corresponding to surveillance,perform one or more actions than can include, but are not limited to,one or more of the following: log the detection of a possibly dangerousitem or a prohibited item; generate a local or remote alarm indicativeof the detection of a possibly dangerous item or a prohibited item; opena gate or door or window to permit access (to all or a portion of atarget area) or close a gate or door or window to block access (to allor a portion of a target area) (and potentially detain an involvedindividual until the proper authorities can intervene); and so forth.

Referring to FIG. 14, at step 960D, corresponding to action recognition,perform one or more (response) actions (with respect to the recognizedaction) than can include, but are not limited to, one or more of thefollowing: providing an audible and/or visual alert; open a gate or dooror window to permit access or close a gate or door or window to blockaccess (and potentially detain or “free” an involved individual) to anarea or a portion of the area; recommend improvements to the performanceof the action that is recognized (e.g., recommending a differentstance(s), hand position, foot position, etc. with respect to a sport,an object used in the sport, and so forth); and so forth.

The system could apply a decision making process to, e.g., a list ofobjects determined by step 960A, in order to determine what type ofaction is being performed (in order to recognize the action) and whattype of response action should be performed in response to the detectedaction type, based on object recognitions. The decision making processcan be any known type of decision making process including, but notlimited to, preprogrammed rules, a neural network, a decision tree, andso forth. It is to be appreciated that the preceding decision makingprocesses are merely illustrative and, thus, other decision makingprocesses can also be used in accordance with the teachings of thepresent invention, while maintaining the spirit of the presentinvention. Hence, the system could determine a person is performing adangerous action (e.g., waiving a weapon (e.g., a knife, a firearm,etc.) and then secure the person within a target area or a region withina target area. The system could provide a user perceptiblerecommendation for a corrective action to the action performed by one ormore users in order to optimize a performance of an action performed bythe one or more users. The action can be a sports or any other type ofaction.

Regarding step 960 and its “sub-steps”, the preceding actions mentionedwith respect thereto are merely illustrative and, thus, other actionscan also be performed in response to object detection and trackingresults. As is evident to one of ordinary skill in the art, theaction(s) taken is(are) dependent upon the type of application to whichthe present invention is applied.

A further description will now be given regarding various aspect of thepresent invention.

In an embodiment, the present invention provides an unsupervisedframework that can successfully adapt the domain of video frames toimages in the feature space without applying any identity label ofvideos. Numerous synthetic face images with degraded quality (e.g.through blurring, down-sampling and JPEG compression, etc.) are used tosimulate the general quality degradation of video frames. Given a facerecognition engine that is pre-trained on an image domain, and by takingthe original and synthetic images, as well as random video frames asindependent inputs, a new engine is adapted to the video domain in thefollowing two ways. First, the representations of the synthetic degradedimages are enforced on the new engine in order to be close to that ofthe original images on the pre-trained engine. Second, a discriminatorwith adversarial learning is adopted that dynamically encourages thevideo frames to have similar feature distributions with that of theimages. Performance is improved through a quality attention module thatrejects extremely low-quality frames.

In an embodiment, the present invention provides a data-driven methodfor image to video domain adaptation which can be used for video facerecognition and other applications, as readily appreciated by one ofordinary skill in the art given the teachings of the present inventionprovided herein, while maintaining the spirit of the present invention.Instead of putting an effort towards collecting large-scale labeledvideo face database, the present invention utilizes large-scaleunlabeled video data to reduce the gap between video and image domainswhile transferring discriminative knowledge from large-scale labeledstill images. To this end, the present invention is configured totransfer discriminative knowledge by distilling the distance metricthrough feature matching from a reference network (RFNet) trained on aweb face database to video face network (VDNet). Meanwhile, we maintaina set of domain specific data augmentations, such as motion blur,resolution variation, or video compression noise, on still images totrain the VDNet to be able to restore the original representation of animage extracted from RFNet. By doing so, VDNet can learn robustrepresentations to various types of noise processes that are potentiallyfound in the real video data. Finally, a domain discriminator isintroduced that learns to distinguish patterns in different domains andis used to regularize the VDNet to reduce domain difference as much aspossible, without the requirement of any supervision such asinstance-level correspondence between two domains or identity labels.Here, the augmented data, which can be considered either as a new domaindifferent from both image and video or as part of the video domain, canbe utilized in a synergistic way to help domain discriminator todiscover domain differences effectively. Furthermore, once trained, thediscriminator can tell which video frame looks like an image based onits confidence score. Discriminator-guided weighted feature fusion isintroduced to highlight representations from more image-like frameswhile discounting representations from more video-like in contrast tohigh-quality web face images.

In summary, some of the more prevalent, but certainly not exhaustivecontributions of the present invention are as follows:

We propose a feature-level domain adaptation to learn VDNet bydistilling discriminative knowledge from a pre-trained RFNet throughfeature matching.

We propose to train with synthetic data augmentation for feature-levelrestoration as well as to help the discriminator to discover domaindifferences.

We propose a domain adversarial learning that modulates VDNet to learn adomain-invariant feature.

We illustrate how the confidence score of the discriminator can be usedto develop an unsupervised feature fusion.

A description will now be given regarding domain adaptation from imageto video, in accordance with an embodiment of the present invention.

While there are large amounts of unlabeled videos captured fromdifferent media sources, labeling a large-scale video database for facerecognition requires much more effort than labeling a set of individualface images as it involves a complicated process of detection andtracking faces in random sequences. There are a few large-scale, stillimage based face databases collected from the web with identity labels.However, the face recognition engine trained on the high-quality webface database may not generalize well to the face recognition in videosas there exists a clear domain difference between images from a web facedatabase and those from video frames as they include different types ofnoise from motion blur, camera out-of-focus blur, or compression.Herein, we introduce a set of objectives for our video face recognitionnetwork (VDNet) that can be trained on large-scale unlabeled video datain V while taking advantage of supervised information from labeled webface images in

.

FIG. 15 shows an exemplary architecture 1500, in accordance with anembodiment of the present invention. The architecture 1500 includesRFNet 1510 and VDNet 1550. The architecture 1500 applies a fixed,pre-trained face recognition engine 1501 in RFNet 1510, and the samenetwork 1503 with partly unfreezing layers, the only part to learn,denoted as domain adaptation (DA) layers 1502 in VDNet 1550. VDNet 1550and RFNet 1510 share weights 1565 there between. As input, in anembodiment, VDNet 1550 receives an original image 1511, a(synthetically) degraded image 1512, and a video frame 1513, while RFNetreceives a high quality image 1514.

A description will now be given regarding distilling knowledge byfeaturing matching, in accordance with an embodiment of the presentinvention.

To take advantage of labeled training data from web face images, wetrain the VDNet 1550 by distilling discriminative knowledge from apre-trained face recognition engine on a labeled web face database,which we call a reference network (RFNet) 1510. Different from previouswork that exploits knowledge via the class probability, we distillinformation by matching feature representations between two networks.Let ϕ(⋅):

^(D)→

^(K) be a feature generation operator of VDNet 1550 and ψ(⋅):

^(D)→

^(K) be that of RFNet 1510. The feature matching (FM) loss is defined onan image xϵ

as follows:

$\begin{matrix}{\mathcal{L}_{FM} = {\frac{1}{\Im }{\sum\limits_{x \in \mathcal{I}}{{{\varphi (x)} - {\psi (x)}}}_{2}^{2}}}} & (1)\end{matrix}$

The FM loss allows VDNet 1550 to maintain a certain degree ofdiscriminative information (from a discriminator 1530) for face identityrecognition. With regards to the network structure, VDNet 1550 can bevery flexible as long as the matching feature has the samedimensionality to that of RFNet 1510. In practice, we use the samenetwork architecture between VDNet 1550 and RFNet 1510. Moreover, weinitialize the network parameters of VDNet 1550 with RFNet 1510 andfreeze network parameters of few higher layers to further maintaindiscriminative information learned from labeled web face database, asillustrated in FIG. 16. That is, FIG. 16 further shows the architecture1500 of FIG. 15, in accordance with an embodiment of the presentinvention. The architecture 1500 applies a fixed, pre-trained facerecognition engine as RFNet 1510, and the same network of convolutionallayers 1580 with partly unfreezing layers, the only part to learn,denoted as domain adaptation (DA) layers as VDNet 1550. The architecture1500 involves feature matching 1571 and adversarial training 1572 toeffectively adapt two domains. For VDNet 1550, three input sources fromrandomly selected face images and frames are adopted. No correspondingsamples and identity labels are required.

A description will now be given regarding adaptation via synthetic dataaugmentation, in accordance with an embodiment of the present invention.

Data augmentation can be used for training very deep CNNs with limitedamount of training data as it allows to prevent overfitting and thusenhance generalization ability of the networks. In addition to genericdata transformation such as random cropping or horizontal flip, applyingdata transformation that is specific to target domain has shown to beeffective. To generalize to video frames, we consider data augmentationby applying transformations such as linear motion blur, image resolution(scale) variation or video compression noise, which are the most typicalcauses of quality degradation in video, and train the VDNet 1550 to“restore” the original RFNet representation of an image without dataaugmentation through the feature restoration (FR) loss as follows:

$\begin{matrix}{\mathcal{L}_{FR} = {\frac{1}{\Im }{\sum\limits_{x \in \mathcal{I}}{_{B{( \cdot )}}\left\lbrack {{{\varphi \left( {B(x)} \right)} - {\psi (x)}}}_{2}^{2} \right\rbrack}}}} & (2)\end{matrix}$

where B(⋅):

^(D)→

^(D) is an image transformation kernel, and

_(B(⋅)) is the expectation over the distribution of B(⋅). Herein, weconsider three types of image transformations with the followingparameters:Linear motion blur: kernel length is randomly selected in (5, 15) andkernel angle is selected in (10, 30).Scale variation: we rescale an image as small as ⅙ of the original imagesize.JPEG compression: the quality parameter is set randomly in (30, 75).

These augmentations are applied in sequence to an image with probabilityof 0.5 for each noise process.

A description will now be given regarding adaptation via domainadversarial learning, in accordance with an embodiment of the presentinvention.

Although data augmentation has been successful in many computer visionapplications, the types of transformation between source and targetdomains are not always known, i.e., there are many more unknown factorsof variation between two domains. Moreover, modeling suchtransformations is challenging even if they are known, and we may needto resort to an approximation of those transformations in many cases.Thus it is difficult to close the gap between two domains. Rather thanputting an effort to guess or approximate different types oftransformations between two domains, we learn transformations betweendomains from the large-scale unlabeled data and facilitate therecognition engine to be robust to those transformations.

The idea of adversarial learning provides a good framework to solve theabove problem, in which the (feature) generator, i.e., VDNet, isregularized to close the gap between two domains, where the domaindifference is captured by the discriminator. Mathematically, theadversarial loss with two domains

and V is defined over the expectation of all training samples:

L _(D)=−

_(x)[ log D(y=1|ϕ(x),xϵ

)−log D(y=2|ϕ(x),xϵV)]  (3)

L _(Adv)=−

_(x)[ log Dy=1|ϕ(x),xϵV]  (4)

The discriminator (D) is defined on top of VDNet that already induceshighly abstract features from deep CNN and therefore D architecture canbe very simple, such as two or three fully-connected layer networks1560.

Note that adversarial loss allows to utilize large volume of unlabeledvideo data to train VDNet without any further labeling effort. However,the loss can only match representations between two domains in a globalmanner and the effect would be marginal if the contrast between twodomains is small or the discriminator cannot distinguish them well. As aresult, we may still want to take advantage of synthetic dataaugmentation with video-related transformations to guide discriminatoreither to realize the difference between domains easily or to figure outadditional domain differences to known (approximated) transformations.This naturally leads us to two different discriminator types, one with atwo-way classifier between image (

) and synthesized image and video (B(

)∪V) or the other with a three-way classifier among image, synthesizedimage, and video.

A description will now be given regarding a two-way classifier network,in accordance with an embodiment of the present invention.

The two-way classifier network uses a 2-way softmax classifier as D todiscriminate between the image domain and the domain of synthesizedimage and video. While the original image are from the image domain,both synthetically degraded images as well as the random video framesare trained to belong to the same domain as follows:

L _(D)=−

_(x)[ log D(y=1|ϕ(x),xϵ

)−log D(y=2|ϕ(x),xϵB(

)∪V)]  (5)

L _(Adv)=−

_(x)[ log Dy=1|ϕ(x),xϵB(

)∪V]  (6)

Since the contrast between two classes becomes apparent by includingsynthetic images for the second class, the transformations in the videodomain that are similar to synthetic image transformations can be easilyrestored.

A description will now be given regarding a 3-way classifier network, inaccordance with an embodiment of the present invention.

The 3-way classifier network uses a 3-way softmax classifier as D todiscriminate the images, synthesized images, and video frames into threedifferent categories.

L _(D)=−

_(x)[ log D(y=1|ϕ(x),xϵ

)−log D(y=2|ϕ(x),xϵB(

))−log D(y=3|ϕ(x),xϵV)]  (7)

L _(Adv)

_(x)[ log D(y=1|ϕ(x)),xϵB(

)∪V]  (8)

Unlike 2-way network, the 3-way network aims to distinguish video framesfrom not only an image domain but also synthetically degraded images.Therefore, it may not learn a VDNet with as strong restoration abilityto synthetic transformations as with 2-way discriminator, but will tryto find additional factors of variation between image or synthetic imageand video domains.

The quality evaluation of each frame of videos is important for videoface recognition since not all frames contribute equally. Moreover, whenthe frame is extremely noisy due to motion blur or other noise factorsand is not recognizable, it is important to dis-count the contributionof those frames in order to highlight the contribution from morerecognizable frames. Training with the domain contrast between image,blurred image and video, the discriminator is ready to provide aconfidence score to each frame being a “high-quality web image”(D=1|ϕ(v))) at test time, whose domain comes with a lot of labeledtraining examples to train a discriminative recognition engine. Finally,with an “imageness” score of the discriminator, the aggregated featurevector for a video V is represented as a weighted average of featurevectors as follows:

$\begin{matrix}{\varphi_{f} = \frac{\sum\limits_{v \in V}{{D\left( {y = \left. 1 \middle| {\varphi (v)} \right.} \right)} \cdot {\varphi (v)}}}{\sum\limits_{v \in V}{D\left( {y = \left. 1 \middle| {\varphi (v)} \right.} \right)}}} & (9)\end{matrix}$

A description will now be given regarding a network implementation, inaccordance with an embodiment of the present invention.

A description will now be given regarding a face recognition engine, inaccordance with an embodiment of the present invention.

There has been a breakthrough in face recognition with the advancementof deep neural networks. Our face recognition engine is also based ondeep CNNs trained on a large-scale web face database. The networkarchitecture is composed of 10 layers of 3×3 convolution followed byReLU nonlinearities with 4 max pooling layers with stride 2 and oneaverage pooling layer with stride 7, except for that our network usesstrided convolution to replace max pooling and maxout units for everyother convolution layers instead of ReLU. The model is trained with adeep metric learning objective called N-pair loss. Different fromcontrastive loss or triplet loss, N-pair loss pushes (N−1) negativeexamples at the same time while pulling a single positive example, whichallows to learn more discriminative representation. In an embodiment,N=1080 is used on 8 GPUs for training. Faces are detected and alignedusing key points and 100×100 grayscale image patches randomly croppedfrom 110×110 resized face images are fed to network for training.

The RFNet is exactly the same as our face recognition engine and theparameters are fixed over the training. VDNet is initialized the same asRFNet but the parameters are updated for all layers except for the lasttwo convolution layers, as illustrated in FIG. 16.

A description will now be given regarding a discriminator, in accordancewith an embodiment of the present invention.

We apply a consistent network architecture of D for both two andthree-way discriminators. In specific, D adopts a multiple layerperception (MLP) structure with two (320−160−3) or three (320−160−80−3)fully connected layers followed by ReLU at every layer except for thelast fully-connected layer, as shown in FIG. 16. For two-way networks,we replace the output channel of last fully-connected layer from threeto two.

A description will now be given regarding various aspects of the presentinvention that provide an improvement over the prior art and/or solve adeficiency of the prior art.

The present invention allows utilizing unlabeled data from a targetdomain for training of a recognition engine and thus better generalizesto the target domain.

The present invention achieves state-of-the-art video face recognitionwithout direct supervision from video data.

Embodiments described herein may be entirely hardware, entirely softwareor including both hardware and software elements. In a preferredembodiment, the present invention is implemented in software, whichincludes but is not limited to firmware, resident software, microcode,etc.

Embodiments may include a computer program product accessible from acomputer-usable or computer-readable medium providing program code foruse by or in connection with a computer or any instruction executionsystem. A computer-usable or computer readable medium may include anyapparatus that stores, communicates, propagates, or transports theprogram for use by or in connection with the instruction executionsystem, apparatus, or device. The medium can be magnetic, optical,electronic, electromagnetic, infrared, or semiconductor system (orapparatus or device) or a propagation medium. The medium may include acomputer-readable medium such as a semiconductor or solid state memory,magnetic tape, a removable computer diskette, a random access memory(RAM), a read-only memory (ROM), a rigid magnetic disk and an opticaldisk, etc.

It is to be appreciated that the use of any of the following “/”,“and/or”, and “at least one of”, for example, in the cases of “A/B”, “Aand/or B” and “at least one of A and B”, is intended to encompass theselection of the first listed option (A) only, or the selection of thesecond listed option (B) only, or the selection of both options (A andB). As a further example, in the cases of “A, B, and/or C” and “at leastone of A, B, and C”, such phrasing is intended to encompass theselection of the first listed option (A) only, or the selection of thesecond listed option (B) only, or the selection of the third listedoption (C) only, or the selection of the first and the second listedoptions (A and B) only, or the selection of the first and third listedoptions (A and C) only, or the selection of the second and third listedoptions (B and C) only, or the selection of all three options (A and Band C). This may be extended, as readily apparent by one of ordinaryskill in this and related arts, for as many items listed.

Having described preferred embodiments of a system and method (which areintended to be illustrative and not limiting), it is noted thatmodifications and variations can be made by persons skilled in the artin light of the above teachings. It is therefore to be understood thatchanges may be made in the particular embodiments disclosed which arewithin the scope and spirit of the invention as outlined by the appendedclaims. Having thus described aspects of the invention, with the detailsand particularity required by the patent laws, what is claimed anddesired protected by Letters Patent is set forth in the appended claims.

What is claimed is:
 1. A face recognition system, comprising: a videocapture device configured to capture a video sequence formed from a setof unlabeled testing video frames, the video sequence including one ormore faces; a processor configured to pre-train a face recognitionengine formed from a reference set of convolutional neural networks(CNNs) on a still image domain that includes a set of labeled trainingstill image frames of faces; adapt the face recognition engine to avideo domain to form an adapted face recognition engine, by applying anon-reference set of CNNs to a set of domains that include the stillimage domain, a synthetically degraded image domain, and the videodomain, wherein the synthetically degraded image domain includes labeledsynthetically degraded versions of the labeled training still imageframes included in the still image domain, and wherein the video domainincludes random unlabeled training video frames; and recognize, usingthe adapted face recognition engine, identities of persons correspondingto at least one of the faces in the video sequence to obtain a set ofidentities for recognized ones of the persons; and a display deviceconfigured to display the set of recognized identities to a user.
 2. Theface recognition system of claim 1, wherein the processor is furtherconfigured to modify, using a discriminator configured to performadversarial learning, the random unlabeled training video frames in thevideo domain to have similar feature distributions to the labeledtraining still image frames in the still image domain.
 3. The facerecognition system of claim 2, wherein an output of the discriminator isapplied on a feature space relating to the random unlabeled trainingvideo frames in the video domain.
 4. The face recognition system ofclaim 2, wherein the discriminator is further configured to perform theadversarial learning using an adversarial loss metric.
 5. The facerecognition system of claim 2, wherein the discriminator is configuredto use a 2-way softmax classifier to discriminate between the stillimage domain and an integrated domain formed from the video domain andthe synthetically degraded image domain.
 6. The face recognition systemof claim 2, wherein the discriminator is configured to use a 3-waysoftmax classifier to discriminate between the still image domain, thevideo domain, and the synthetically degraded image domain.
 7. The facerecognition system of claim 2, wherein the discriminator is configuredto assign a respective confidence score indicative of a degree ofquality to each of the unlabeled testing video frames in the videosequence, and the processor is configured to reject any of the unlabeledtesting video frames in the video sequence having the respectiveconfidence score below a threshold value.
 8. The face recognition systemof claim 2, wherein the discriminator is implemented by a multi-layerperception structure with fully connected layers, each followed by arespective rectified linear unit.
 9. The face recognition system ofclaim 1, wherein the set of domains further includes another still imagedomain that, in turn, includes random still image frames with respect tothe still image domain and the synthetically degraded image domain. 10.The face recognition system of claim 1, wherein the syntheticallydegraded versions of image frames included in the still image domain, inturn, include blurred image frames and compressed image frames.
 11. Theface recognition system of claim 1, wherein the synthetically degradedversions of image frames included in the still image domain have beensubjected to one or more transformations relative to the set of labeledtraining still image frames.
 12. The face recognition system of claim 1,wherein pre-training of the recognition engine is performed by matchingfeature representations between the set of reference CNNs and the set ofnon-reference CNNs.
 13. The face recognition system of claim 12, whereinmatching feature representations comprises computing a feature matchingloss for an image frame processed by the set of reference CNNs and theset of non-reference CNNs, and wherein discrimination informationrelating to object recognition is determined based on the featurematching loss.
 14. The face recognition system of claim 1, wherein theprocessor is configured to adapt the recognition engine by training therecognition engine to restore an original representation of a stillimage frame without data augmentation based on a feature restorationloss.
 15. The face recognition system of claim 1, wherein the processoris further configured to grant the at least one person access to anobject or a facility, responsive to the set of recognized identifiesincluding the at least one person.
 16. The face recognition system ofclaim 1, wherein the processor is further configured to restrict the atleast one person access to an object or a facility, responsive to theset of recognized identifies excluding the at least one person.
 17. Acomputer-implemented method for face recognition, comprising: capturing,by a video capture device, a video sequence formed from a set ofunlabeled testing video frames, the video sequence including one or morefaces; pre-training, by a processor, a face recognition engine formedfrom a reference set of convolutional neural networks (CNNs) on a stillimage domain that includes a set of labeled training still image framesof faces; adapting, by the processor, the face recognition engine to avideo domain to form an adapted face recognition engine, by applying anon-reference set of CNNs to a set of domains that include the stillimage domain, a synthetically degraded image domain, and the videodomain, wherein the synthetically degraded image domain includes labeledsynthetically degraded versions of the labeled training still imageframes included in the still image domain, and wherein the video domainincludes random unlabeled training video frames; recognizing, by theprocessor using the adapted face recognition engine, identities ofpersons corresponding to at least one of the faces in the video sequenceto obtain a set of identities for recognized ones of the persons; anddisplaying, by a display device, the set of recognized identities to auser.
 18. The computer-implemented method of claim 17, wherein theprocessor is further configured to modify, using a discriminatorconfigured to perform adversarial learning, the random unlabeledtraining video frames in the video domain to have similar featuredistributions to the labeled training still image frames in the stillimage domain.
 19. The computer-implemented method of claim 18, whereinan output of the discriminator is applied on a feature space relating tothe random unlabeled training video frames in the video domain.
 20. Acomputer program product for face recognition, the computer programproduct comprising a non-transitory computer readable storage mediumhaving program instructions embodied therewith, the program instructionsexecutable by a computer to cause the computer to perform a methodcomprising: capturing, by a video capture device, a video sequenceformed from a set of unlabeled testing video frames, the video sequenceincluding one or more faces; pre-training, by a processor, a facerecognition engine formed from a reference set of convolutional neuralnetworks (CNNs) on a still image domain that includes a set of labeledtraining still image frames of faces; adapting, by the processor, theface recognition engine to a video domain to form an adapted facerecognition engine, by applying a non-reference set of CNNs to a set ofdomains that include the still image domain, a synthetically degradedimage domain, and the video domain, wherein the synthetically degradedimage domain includes labeled synthetically degraded versions of thelabeled training still image frames included in the still image domain,and wherein the video domain includes random unlabeled training videoframes; recognizing, by the processor using the adapted face recognitionengine, identities of persons corresponding to at least one of the facesin the video sequence to obtain a set of identities for recognized onesof the persons; and displaying, by a display device, the set ofrecognized identities to a user.